SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1b662fe0aa2c95e319d50a0726ade2ad2eaca9455f3db6a7c8ddf92242fdd1a' 
  AND token = 'NrW6/noaDBVvenn8aMXAIDLsQbUX7Ugo2qRnqVAmOXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}